Liquid heater



April 17,1945.. H. J. D N. Mc'cLLuM LIQUID-HEATER Filed July 27,' '1942:s sheets-sheet 1 wk. ww .NW %N wm..

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, fauci@ April 17 1945 H. J; DE N; MccoLLUM LIQUID HEATER Filed July2'7, Y 1942 5 Sheets-Sheet 2 April 17,1945'. Y H. J.' DE N. MccoLLuM2.5373767 LIQUID HEATER Filed July 27,' 1942 5 Sheets-lSheet/S A IPatented Apr. 17,1945

" Henry J. De N. McCollum, Chicago, Ill.; Thelma lMcliollum executrix orsaid Henry J. De N.

McCollum, deceased e Appiiontion Jniy'zi, 1942,'serini No. 45ans e I 5claims. (ci. zas- 32) The present invention 'relates to liquid. heatersandis more particularly directed to liquidheaters of the internallcombustion type adapted for use in aircraft or other vehicles in whichmaximum heat production is desired from a. heater of minimum size andweight;

A typical use for'a heater of this type is toptovide a source of'hotwater for use on large airplanes of the type which vmust remain' awayfrom their bases for extended periods.r This hot water may be needed forwashing, shaving and other purposes. Another typical purpose for which aheater vof 'this type may be used is forheating a liquid which is thencirculated through radiators `in the space occupied by the crew; Forthis purpose glycol is'the liquid frequently used as a. heat exchangemedium. VThese uses are merely illustratlve and others will be apparentfromthe following description.

It is an object of my invention to provide an other liquids.

A' further object is to provide an improved internalcombustion liquidheater which maintains Fig. is a back view of a portion of the mechanismillustrated in Fig. 4; and

Fig. 6 is a front elevational View of ,a portion or the mechanismillustrated in Figs. 4 and 5.

Heaters of the' type to which the present invention relates are suppliedwith a combustible mixture of air and fuel, such asgasoline from acarburetor or, --when utilized on a vehicle having an internalcombustion engine superchar'ger, the combustible mixture can b e drawnfrom the outlet of the supercharger. Normally, ilow of combustiblemixture through the heater is produced improved heater of the internalvcombustion type i particularly adaptedfor lheating water, glycol or thetemperature of the liquidsubstantially constent regardless of thequantity' of liquid passed through .the heater.

A further object is to provide an improved internal combustion typeliquid heater which can` `be economically' constructed, which will behigh- 1 ly eilicient, which will operate 'satisfactorily under varyingconditions, which -will be small in size and weight,y and which willhave along, useful life.

" Other objects will appear from the following description of apreferred embodiment of my invention. i

In the drawings in which similar characters of reference refer tosimilar parts throughout theseveral views:

Fig. 1 is a side elevation of a heater embodyshown in longitudinalsection;

Fig. 2 is a transverse sectional view takenjn by a pressure diierentialbrought about either by connecting the exhaust outlet of the heater to asuction producing apparatus, or by connecting the'combustible mixtureinlet to a source of com- For instance,

bustible mixture under pressure. when the heater is used in conjunctionwith a vehicle having anon-supercharged internal combustion engine, flowcan be produced' through thev heaterv by connecting the exhaust heateriltting to the intake manifold of the vehicles internal combustionengine. If the vehicle engine is supercharged, combustible mixture canbe fed' under pressure from the'supercharger in which case no suctionproducing means is needed at the exhaust fitting.

In Figi of the diawingssvalve iitting'` in has its inletend I2internally threaded for attachment to. a.' conduit through whichvcombustible mixture is supplied to the heater.o Within the tting l0 islocated a throttle valve of the butteriiy type. This' valve is not shownbut the rotatable shaft on which it is mounted is indicated by lthenumeral I4. This throttle valve by its position controls the rate offlow of combustible mixture through the heaterapparatus.

ing thepresent invention with la portion thereof y its the directionindicated by theallows' along the Fig.l 3 is a transverse sectional viewtakenin i theev direction of the arrows along the `line -3-34 i is o.freetionei side elevation of .uo-

per left hand fraction of Fig. l'drawn to largerl The lower end oi? thefitting I0 is tubularand contains a bundle of small diameter tubes' I6formed of a metal having good heat conducting properties, such ascopper, for'instance. 'I'he sum of the bores through these tubestogether with the spaces between the tubes provides a passagethatoil'ers little resistance to the ilow of com- A- -bustible mixturetherethrough'. 'I'he `tubes, however, prevent flame from ashing .backinto the Avalve Ill-in a well known manner.

'I'he valve fitting I0 is suitably secured to an elbow-shaped casting i8having a hollow portion H2li whichr serves as 'a combustion chamber, the

combustible mixture entering this chamber 1 through .radial ports 22located below the ame scale with portions thereof broken awaytoillustrete the nieehenism interiorly thereof;

arrester I6. I'he radial ports .22 are formed by striking out vanes fromacylindrical member and 50, for instance.

therefore the ycombustible mixture enters the `combustion chamber 20with a swirling motion.

' Within the combustion chamber, the combustible mixture is ignited byan igniter-plug 24 of the hot wire type, which is threaded through aboss 28 formed as a portion of the casting I8. Inasmuch as it may bedesirable in diierent installations to have the igniter plug 24on'diilerent sides of the heater, two threaded bosses 28 are providedopposite each other. The igniter is screwed into either one of thesebosses, While the other is closed by a plug 28. If desired, two ignitersmay be used in some installations. The igniter 24 is of the hot wiretype in which the .wire resistance element is electrically heated to atemperature suiilcient to initiate combustion of the mixture flowinginto the combustion chamber. Once the combustion has been initiated, theigniter 24 can be deenergized either manually or thermostatically,inasmuch as a reigniter .i8 serves to re-kindle the combustible mixtureif for any reason combustion should be temporarily interrupted.. Thereigniter 30 comprisesv a spirally wound sheet of inconel or other heatand vcorrosion resistant metal which is quickly heated by the combustionwithin the combustion chamber to a temperature suilicient to kindle thecombustible mixture. This reigniter is, more fully disclosed in mycopending application Serial No. 410,039 iiled September 8, 1941. Forconvenience. the reigniter 38 is secured to the end of a plug 82threaded into'a boss 34 formed at the end of the casting I8.

From the combustion chamber within which the combustible mixture isburned, rthe hot products of combustion pass through a heat exchangetube 38, the inlet end of which is provided with a ilange 38 secured tothe combustion chamber casting |8 by means of cap screws 40, the jointbetween the members being sealed by a gasket 42.

Within the heat exchange tube 38 the hot products of combustion passaround a cylindrical muler structure 44 spaced from the side wall of thetube 38 by a plurality of `longitudinally extending ribs 48, thestructure thereby providing a. plurality of longitudinally extendingchannels which straighten out the eddies in the hot products ofcombustion so as to produce a smooth llow. The side Wall of thecylindrical structure 44 is provided with a multiplicity ofperforations-48 while the interior is packedA with sound dampingmaterial, such as stainless steel wool The arrangement thus provideddamps out pulsations in the hot products of combustion, and serves as amuiller to quiet the operation oi' the heater as well as preventingperiodic pulsations of the type known as motor boating.

The hot products of combustion leaving the heat exchange tube 38 arecollected inan L- shaped'end cap 52 and are passed outwardly` through anexhaust fitting 54 threaded for at-v tachment to an exhaust conduit tobe connected to a space of lower pressure than that of the fuel l'mixture supply. At its inner end the exhaust iltting 54 is threaded intothe end cap 82 and has a Venturi shaped restricting tube 58 which servesto stabilize the rate. of' ilow of combustible mixture through thesystem by compensating for f The heater so mdesoribed operates to hootthe heat exchange tube 38 and this heat is transferred to a tube 58 ofcopper or other good heat conducting material wound therearound inclosely formed turns, .the inlet end of this tube being wound back uponitself and connected to an inlet fitting threaded into the casting AI8where it communicates with a bore 82 leading t0 a cored out liquidjacketing space 84. 4This liquid jacketing space 84 formed in the casingI8 substantially completely surrounds the combustion chamber, and atalow point on the casting I8 is connected by means of an internallythreaded spud 68 to a liquid inlet tting 88, this ilttng in turn beingconnected to an inlet pipe 1I).

The opposite end of thetube 58 passes outwardly through a sheet metalshell 12 .which encloses the combustion chamber and heat exchangeportions of the apparatus and is connected to a fitting 14 threaded intoa longitudinally extending header tank 18. This tank extends. from aposition adjacent the outlet fitting 54 nearly to the inlet tting I2 andnear its forward end is connected on the opposite side to an outlet pipe18.

At its forward end the tank 18 is ilanged and is secured by screws 88 toa similar ilange on a cap 82, this cap having a forwardly extendingvertical web-like member 84 secured byscrews 88 to the inlet fitting I8,thereby forming a solid structure. The inner face of the cap 82 isformed to provide a threaded cylindrical recess into which one end of athermostatic tube 88 is thread'- ed. This tube contains a themostaticbellows 90 closed at its inner end bya plug 92 sealed to `the inner endof the tube 88. 'I'he opposite or forward end of the bellows is attachedto a plunger 94 which extends through an opening 88 in the cap 82'withits outer end in a position subjecting through the cap 82 so that liquidwithin the header tank 18 can circulate through the tube 98, thusbringing the liquid within thetank into intimate heat transfer relationwith the liquid within the bellows 80.

The outer end of the plunger 94 is seated in a slotted socket |08 formedin the edge of a lever |02 pivoted at its lower end upon a transverselyextending pin |84 secured to the inlet member III. The upper end oftheqlever |82, therefore, is free to move backwardly and forwardly underthe influence of similar movement of the plunger 84. This lever isbiased against the end of the plunger by a grasshopper sprlng |08 coiledabout the pin |04 with its uppzer end resting against the face of thelever opposite the-plunger 94, while its lower end rests in a slot in anabutment |08 formed as a projection on the web 84 of the cap 82. Theupper end of the lever arm ||i2l is .of thinner vsection than the lowerportionI so as to provide an upstanding thin nnger IIIl transverselyslotted as indicated at H2, This miser is located within alongitudinally extending slot I I4 formed in a downwardly extending armI|8 clamped'at its upper end to the bottoms-'valve smit u. 'A

asvavcr slot ||2 in the upper end of the lower lever lill and is securedat its ends in the upper lever H6. Thus, fore and aft movement of theupper end oi' the lower lever |02 will be transmitted to the upper arm II6 through the pin ||8 so as to cause similar fore and aft movement ofthe lower end obtained by lthe use `of substantially the same `oreuuivalentmeans.4 e

Iclaim:

of this upper arm. This angular motion is in turn. i

transferred to the shaft I4, thereby causing the buttery valve partiallyto .be closed upon expansion of the'bellows 90.

In order to prevent rattles and to take up any lost motion which mayexist, the arm ||6 and the lever |02 are connected to opposite ends of alight weight floating grasshopper spring |20.

The motion of the arm IIB and hence the rotationv of the shaft |4 islimited by a .stop member |22 clamped to the shaft ||4 by screw |24.This stop member has an outwardly radiating'iinger.

|26 which moves back and forth with rotation of the shaft |4 in a slot|28 formed in the edge of a cup-shaped member |32 press-fitted over acylindrical surface |34 formed as a portion of the inlet fitting castingI0.. Thus the shaft |4 is free to rotate back and forth upon contractionv and expansion ofthe bellows-90 until the finger |26 is brought againsteither the forward or back` ward end of the slot |28, beyond which nomotion can take place. l

Assuming that with a heater of the above type properly installed, it isdesired to supply hot 1iq` uid,v such as water or glycol, the heater isstarted, that is, a iiow of combustible mixture is produced .through thedevice and the igniter 24 is energized. This initiates combustion of thecombustible mixture, soon after which the igniter can be deenergized,inasmuch as the reigniter 30 will immediately re-kindle the combustiblemixture if combustion for any reason momentarilyfails. The hot productsof combustion pass through the heat exchange portion of the apparatusand transfer the .heat therein to the heat exchange.

l. In a liquid heater, the combination of -an internal combustion typeheater having means forming a combustion chambenand a heat ex' changeconduit connected to said combustion chamber and adapted toreceivethe'hot products y l of combustion therefrom, an inlet connectionadapted to be connected to a source of combustible mixture, a throttlevalve in said inlet connection, conduit means for conveying combustiblemixture from said throttle valve to said combustion chamber, liquidconducting means in heat exchange relation with said heat exchangeconduit, a headerl connected to one end of `said liquid conducting meansand adapted to receive and s tore the liquid after it has beencirculated through said liquid conductingA means, lthermostatic bellowsmeans arranged in heat exchange relation to the liquid in said header,and means,

I ,operated .by expansion and contraction of said bellows means forpartially opening and closing said throttle valve. g

2. vIn a liquid heater, the combination of an internal combustion .typeheater having means forming a combustion chamber, and heat ex'- -changemeans connected to said combustion chamber and adapted to receive thehot'products;

of combustion therefrom, conduit means adapted to convey combustiblemixture to said combustion chamber, throttle valve means in said conduittube B8. 'I'he liquid passing through the liquid jacket space 64 andthrough the tube 58 is, therei'ore, heated, and passes into the headertank 16 from which it is withdrawn through `the pine 18. After theliquid within the header tank 16 has reached the desired operatingtemperature. the ether or other substance within the bellows 90 will bevaporized. thus causing the bellows to expand somewhat. This movement ofthe bellows is transferredthrough the plunger 94 to the lower lever |02and rocks the upper end of this lever forwardly, the motion beingtransferred by the pin ||8 to the upper arm H6. This motion in turnproduces rotation of the butterfly valve I4.

thus restricting the opening through the inlet .fitting I0, therebydecreasing the rate of flow of combustible mixture through the heater.With this system it will be seen that the higher the ications andvariations' may be made Awithout l departing from the underlyingprinciples' of the invention.` I therefore desire, by the followingclaims, to include within -the scope of the .invention all suchmodications and variations by which substantially the results thereofmay be i 4.In afliquid heater, the

internal combustion type vheater having means means, liquid conductingmeans in heat exchange relation with s aid heat exchange means tointerchange heat from the hot products of combustion to the liquid insaid liquid conducting means, a header for receiving the4 heated liquidfrom said lliquid conducting means, thermostatic means connected tooperate said throttle valve and adapted to alter the setting of saidthrottle valve upon an increase or decrease in temperature of the liquidin said header, and means to interchange heat between the liquid in saidheader and said thermostatic means. A

3. In a liquid beaten4 the combination of an interna] .combustion typeheater having means e forming` a combustion chamber, and a heatexchanger connected to said combustion chamber and adaptedto receive thehot products of cornbustion therefrom, an inlet connection. adapted tobe connected to a source of combustible mixture, a throttle valve insaid inlet connection, conduit means for conveying combustible mixturefrom said'throttle valve to said combustion chamber, liquid conductingmeans inheat exchange relation with said heat exchanger to interchangeheat .from the hot products of combustion to the liquid in said liquidconducting means, a header for receiving the heated liquid from saidliquid con.- ducting means, .thermostatic means arranged in heatvexchange relation to the liquid in said header,`

means operated by expansion andv contractionof said thermostatic meansfor partially opening and closing said throttle valve, and stop meansto. limit the movement of said, throttle valve to less than the fullrange of movement provided by said g thermostatic means, whereby theamount of heat produced by the internal vcombustion heater will varyinversely with the temperature of the liquid in said header. 5

combination of an forming a combustion chamber, and a heat exchangerconnected to said combustion chamber bustion therefrom. an inletconnection adapted to be connected to a source of combustible mixture, athrottle valve in said inlet connection, conduit means for conveyingcombustible mixture from said throttle valve to said combustion chamber,liquid conducting means -in heat `exchange, relation with said heatexchanger to interchange heat from the hot products of combustion to theliquid in said liquid conducting means, thermostatic means arranged inheat exchange relation to the liquid issuing from said liquid conductingmeans and responsive solely to the temperature thereof, and meansoperated by expansion and contraction of said thermostatic means forpartially opening and closing said throttle valve.

5. In a liquid heater, the combination of an internal combustion typeheater having means forming a combustion chamber and heat exchangechange relation with said heat exchange means to interchange heat fromthe hot products of combustion to the liquid in said liquid conductingmeans, a header connected to said liquid conducting means for receivingthe heated liquid, a'

thermostatic element in heat exchange relation to th'e liquid in saidheader a throttle valve operated by said thermostatio element, saidthrottle valve being located in said conduitl means, and a housingenclosing the internal combustion type 'heater and said liquidconducting means and separating them from said header and saidthermostatic element,

HENRY J. DE N. McCOLLUM;

